1. Field of the Invention
The present invention relates to an air filter device to provide filtered air to an internal combustion engine.
2. Prior Art
Air filters and air cleaners are well known to provide a source of filtered air to an internal combustion engine. In one type of filter, a housing is provided having an air inlet at its small end and an air outlet at its large end for directing flow of air into and out of the housing. The air filter device itself has a filter element coaxially arranged to the interior of the housing. The filter device fits within the housing and may have either a cylindrical or frusto conical shape. With the frusto conical shape, the diameter upstream is smaller than the diameter downstream. The base of the filter includes a flat ring which is received within the housing and becomes sealably engaged with the housing.
The filter element includes a series of circumferentially arranged pleats. By directing airflow between the pleats a distance axially before passing though the filter, the efficiency and capacity of the air filter is increased and the pressure drop decreased. By evenly distributing airflow, all of the filter media is used.
It is known that additional filter area will increase the filtering capability and will lower the average air flow face velocity. The radial dimension of the filter at the base ring is, however, limited because of the size of the housing.
Additionally, as the radial dimension or width of the pleat increases, it is less rigid and more prone to vibration.
There is a need, therefore, for an air cleaner and air filter device that will maximize the amount of filter area in a given housing space.
There is also a need for an air cleaner and filter device that maximizes axial air flow and minimizes air flow change in direction.
There is further a need to provide maximum rigidity and structural support to the pleats of the air filter media.
There is an additional need for an air cleaner and air filter device that minimizes turbulence.